M 120
The amount prepared is in excess of that of the previous year; partly because of the greater number of calves vaccinated and partly because of the greater yield of lymph obtained per calf.
Experiments were carried out to determine a method of vaccination which would produce a greater yield of lymph than had been heretofore obtained. It was hoped that the method advocated by Stuart and Krikorian (Ann Trop. Med. & Parasit. 24: No. 4, 527, 1930) would be an improvement, but it was abandoned after careful trial; in our hands it offered no advantages. Ultimately we adopted the simple expedient of spacing the lines of insertion definitely closer together than had been our previous practice. The result was quite satisfactory, as the figures for the year show a 20% increase in the yield of lymph obtained. This should materially lower the cost of production.
The routine of bacteriological control of the finished lymph before issue has also been brought nearer to the ideal. In addition to previous procedures plate counts are now done and potency tests on rabbits performed with graded dilutions. Through the kindness and cordial co-operation of the Medical Director and staff of the Alice Memorial and Affiliated Hospitals we are now able to have potency tests performed on new-born babies on every batch of lymph before issue. At the present moment for this purpose we are using lymph of full strength as well as a dilution 1 in 5 in each case. The possession of definite evidence of the potency of every batch of lymph issued is a valuable safeguard against possible loose criticism of our lymph as well as being a useful check on our own methods of production.
E. PREPARATION OF VACCINES AND SERA.
The work under this head has been very heavy for the year reported. This has been due chiefly to the epidemic of cerebro-spinal meningitis referred to in a previous paragraph which necessitated putting up and distributing large quantities of anti-serum. The stock of antiserum prepared and on hand in cold storage was adequate to meet the demands of the situation but we are left with the task of replenishing it to the previous figure with a view to the possibility of a similar demand at any time in the future. From the clinical data available it appears that the serum has been therapeutically efficacious.
The total amount issued was 29,360 c.c. Of this amount 6,240 c.c. was exported to Macao on the request of the health authorities there.
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